I might add a little clarification here:

1.- Macrobatteries damage will be reduced by the target's armor. If reduced to zero or less, then the defending ship (B) will take no damage (unless it was a critical hit, because you will roll in the table anyway. If there are still damage remaining after applying the armor's protection, apply that excess to Hull directly (and remeber each point of hull lost means a loss of 1 morale and 1 population also).